How many calories should I eat a day
Depending on what goal you set for yourself - losing excess weight or gaining muscle mass - you need to maintain a daily deficit or surplus of calories. This can only be done after calculating the TDEE (total daily energy expenditure) indicator - the total daily energy expenditure, which depends on physical activity. There are several ways to determine this value.
How to calculate daily calorie intake
Today, TDEE can be determined using special formulas (many of which were obtained back in the 19th century), and online calculators with built-in algorithms and empty fields for entering values: age, sex, weight, etc. In a simplified the formula looks like this:
- TDEE = BMR × A, where A is the daily activity ratio.
To find out the appropriate coefficient, you need to use special tables, and BMR is calculated using separate formulas - taking into account secondary parameters, and is equal to energy consumption at rest (without physical activity), and at a comfortable ambient temperature (18-20 degrees) .
Difference between TDEE and BMR
If the first takes into account the total energy consumption - taking into account physical activity, then the second - only the consumption at rest (for heartbeat, respiration, digestion, temperature regulation, and other "autonomous" biological processes).
The most common way to determine TDEE today is the modified Mifflin-St. Jeor formula, which looks like this:
- (10 × m + 6.25 × h − 5 × t + 5) × A for men.
- (10 × m + 6.25 × h − 5 × t − 161) × A for women.
Accordingly, m is body weight (in kilograms), h is height (in centimeters), t is age (in years), A is the level of physical activity (determined from the table).
The second most popular formula for calculating TDEE is the revised Harris-Benedict equation. In 1984, it acquired its final form:
- TDEE = (88.362 + 13.397 × m + 4.799 × h − 5.677 × t) × A for men
- TDEE = (447.593 + 9.247 × m + 3.098 × h − 4.330 × t) × A for women
The letter designations in this case are identical to the Mufflin-St. Jeor formula: m is body weight in kilograms, h is height in centimeters, t is age in years, A is the coefficient of physical activity.
In addition to the Mufflin-St. Jeor and Harris-Benedict calculations, there are also Owen formulas, Almajwal-Abulmeati, Lewis, etc. The highest TDEE values are usually shown by the Almajwal-Abulmeati formula, and the lowest by Owen. The results of the calculations of Mufflin - St. Jeor and Harris - Benedict are in the interval between them, and can be considered a universal golden mean.
Sometimes an additional value TEF is used in calculations - the thermal effect of food. It determines how much energy the body spends on the digestion of proteins, fats and carbohydrates. On average, 10% of the daily energy expenditure is spent on digestion, and this value is included in the BMR, and, accordingly, in the TDEE: after multiplying by the activity coefficient.
Weight Loss Facts
- Eating less does not mean losing weight quickly. On the contrary, a sharp decrease in calories consumed will put the body into a state of stress and energy conservation. A significant part of the carbohydrates consumed will be stored as fat "in reserve" - despite the fact that you will constantly feel hungry. Therefore, reduce your daily calorie intake gradually over many weeks or months.
- It can take up to 80 hours for food to completely pass through the digestive tract. At the same time, approximately 10% of the body's daily energy will be spent on its digestion. The "heavier" the food, the more difficult and longer it is digested. Most vegetables and fruits are classified as "light" food, and almost all fried and meat dishes are "heavy".
- If you wish, you can lose weight even eating candy alone. In 2010, this was proven by Professor Mark Haub from Kansas. For two months, he ate only sweet bars and candies, never exceeding the 1,800 kcal/day mark, and occasionally varied his diet in the form of chips and snacks. Oddly enough, from such a diet, he managed to lose 12 kilograms and reduce his body mass index (BMI) by 4 units. But the research results did not include information about the harm such food caused to the professor's body during the 60 days of testing.
- The calorie content of food depends very much on the method of its preparation, sometimes several times. For example, raw chicken breast contains 136 kcal, baked - 220 kcal, and fried - 312 kcal. The number of calories also increases markedly if you cook food with vegetable and animal fat (sunflower or olive oil, margarine).
